Hey guys,
I was reading through the forum for a while about rough idle and engine hiccups at stop lights or accelerating.
CEL came up a couple of times but it went off after two seconds with no code memorized in the ECU.
This started for my car couple of months ago so I start troubleshooting.
Unfortunately I have 52000 miles, so just out of warranty.
This is what I did do far

• first I change the spark plugs with Denso iridium - no fix
• second I changed the coil packs (all 4) - no fix
• third I tried Heat water removal twice - no fix

Today it have a rough acceleration from the stop light and CEL came on and stayed on.
I read the codes and it says P0303 and P0304 - multiple misfires in cylinder 3 and 4.
With the new spark plugs and coils I am ruling out an electrical problem.
Has anybody got to the bottom of this?

 

I had a very similar problem. P0303, along with P0403, P0203, P0203, P055, C1555. I replaced spark plugs, coil packs, and took it to dealer to run an electrical diagnostic test. Their diagnostics said everything was fine, and they couldn't fix the codes, even after a valve adjustment. They said it's a valve problem, not seating, or something. So I took the head off, took it to a head shop for a vacuum test, even though I knew better that that could not possibly be the problem but giving the dealer the benefit of the doubt, and it tested normal/good.

I went to a salvage yard and bought a used engine with 42k miles, swapped it with my engine, and the result is my 2007 Fit Sport runs perfectly now. There is none of the hesitation or code throwing as before.

One thing I thought of after all this is that there may be a leak somewhere in the plastic portion of the intake manifold. I did not ever test it. I have the old manifold along with all the sensors and throttle body attached to it still. I might swap it with the replacement engine manifold and see if the problem comes back.

There's a serious problem with the 2007s, IMOP.

 

Another correlation that I have noticed was that it get worse when the gas tank is getting empty. Once I fill up is not as bad and even the CEL went away.
No clue what it can be.

 

The car is day and night even at a 1/4 tank down. I try to stay full all the time. Its scares me to think that one day i may have these problems with my car and need an engine swap just to repair.

 

That's very peculiar that you run better with more fuel. I can only think more tank fuel means more pressure at the fuel pump inlet. However, when I did my swap the problem went away and I kept the same fuel system.

I'm contemplating selling the Fit, even though it runs well now. I fear a recurrence. I'd rather buy a set of know problems with another brand or model then unknown, as with the Fit's stutter issues. I got my salvage engine for just $250 at lkqonline.com but I think the more usual price is 500 to 1,000.

 

After another year mystery is solved.
I had to replace all coils and spark-plugs, but let me give you the entire story.
I was getting inconsistent CEL errors - EGR valve, air intake mass sensor and I decided to take it to Coggin Honda of Orlando again, to test it on the Honda computer.
They said that the missfire and stuttering issues are due to bad coils and spakplugs after charging me $120 and waiting 4 hours for the test.
I have changed the coils and the spakplugs before, but I said maybe there were not Honda compatible parts and I asked them for a quote.
They came back with $970 with $570 in parts and $400 to replace 4 coils and 4 sparkplugs.
I checked their part store at the dealer and the parts were 20% cheaper in their own store than they were charging me.
They asked $32 for a NGK iridium sparkplug where Advanced Auto Parts across the street had them for $12 and basically $100 labor for each coil and sparkplug change.
I end up getting the coils from Honda parts store, the sparkplugs from Advanced Auto Parts - they even gave me a discount the cashier felt bad that they are so expensive, so I got them for $10 each.
I took my time and remove the coils and the sparkplugs, clean the threads and use antiseize and dielectric grease to put all the new parts in and two hours later I got a nice running Fit, even better than new.
This takes me to the second part, when I was at the dealer a lady came with a 2008 Honda Fit with the same stuttering issue. Should I suspect that Honda got a batch of bad coils in 2007 -2008? We'll never know.
Never go to Cogin Honda of Orlando dealership, they overcharge and unprofessional.
Thank you for your support on this forum.

 

Good to hear you solved your problem. If I had changed all my packs instead of just two, I might have avoided engine replacement. It also would have helped if my dealer even suggested that instead of charging me for an unnecessary valve adjustment. The tappets weren't even loud. Also, I've found dealer parts, sales, and service are really three different companies operating in the same bldg. Many times I was charged for a part by service that was at least 20% more than what a separate quote from parts provided. Then I'd go back to service and give them the WTF, and they'd apologize and credit me. Caveat emptor. If dealer offers to give it to you in the arz, and you accept, they will gladly put it in your arz.

 

One other thing. I had coil packs go out on my odyssey and the thrown codes were unrelated and would misguide a troubleshooter. . Just had to go by my experience with the fit. Replaced the offending pack, but then the adjacent one went out 2 weeks later. They go in pairs it seems.

 

Great info. I have a 2007 with 50k miles and my car runs about the same no matter what the fuel level. The only thing is that I tend to get real bad mpg, about 18 Mpg. Granted I live in the city but I don't idle much. I've been reading on amazon.com in the customer reviews on coil packs that some change their CPs and get much improved mileage. Apparently bad coils can cause the Fit to run much too rich.

what brand coil pack would you recommend? I've seen many different prices. Some are made in Korea apparently.

 

I have not found anything online that describes the differences in coil packs between 1 vendor or another.I also haven't read anything to indicate cheaper packs are worse than the more expensive packs.

 

I've got a 2008 Fit, 275K miles.

After getting the stutter, buck, and slow acceleration for a while, slowly getting worse, it finally threw a code, p0303, and then a p0304. After reading the forum, I swapped in a new coil pack for #3 and that seems to have fixed the problem. I may go ahead and do the other 3 too, since it's not running as well as new, but then, maybe it never will again given the miles.

From my experience, if it runs poorly at 110K+, it's the O2 sensor. New ones last longer than the original for some reason, IF you use Bosch at least.

If it stalls at the first full stop when started cold, adjust the valves. They ALL probably need this at 75K, but it'll get worse by 100K or 130K. I bet mine needs it again, but I'm past proactive maintenance.

New plugs definitely make sense at 100K miles, even with highway miles. And maybe a little more after that. I swapped my again last fall, and the gaps were a bit wide today on #3 so I narrowed it a bit.

All of these things are easy. The Fit is perhaps the easiest to do valves on of any car I've done. Coil packs are simple. Plugs aren't hard. O2 sensor is easier than most.

Injectors look easy too, but I have yet to do those.

So, I'm shooting for 300K mi and calling it good. It's been a most excellent vehicle.